Dr. Mona Hanna-Attisha’s medical training and environmental justice background prepared her to analyze health records and discover a doubling of blood-lead levels after Flint switched its drinking water source. But it’s her courage, compassion and commitment to children that make her a hero of the Flint water crisis. While Hanna-Attisha insists that she was simply doing her job, few would have shown the resolve to stand by her data and continue spreading the word in the face of attempts by state officials to discredit her. When the state at last admitted she was right, Hanna-Attisha spoke on behalf of the city’s kids with the authority of a doctor and the passion of a parent, testifying before Congress, speaking with countless journalists and appearing on TIME’s 100 Most Influential People list. She helped to launch a new fund dedicated to the healthy development of Flint children and is leading an innovative public health program to give them the tools they need to succeed. A lifelong environmental advocate, Mona Hanna-Attisha is an effective champion for the people of Flint and a model of what public service looks like.

As passionate about justice as she is meticulous in its pursuit, Pam Taylor has made it impossible to ignore the links between industrial agriculture and the degradation of water resources. Taylor volunteers about 40 hours a week with Environmentally Concerned Citizens of South Central Michigan sampling rural waterways, compiling data and presenting her findings in ways the public can understand. Following the 2014 toxic algae outbreak that left 400,000 Toledo-area residents without safe drinking water, she used the Freedom of Information Act to build the first comprehensive database of concentrated animal feeding operations in the Western Lake Erie Basin. Her findings not only confirmed her suspicion that manure from CAFOs was a major, largely overlooked driver of Lake Erie’s algae problem, but also showed huge federal subsidies pouring into the region’s megafarms, even as they violated the Clean Water Act. Fearless, resolute and humble, Pam Taylor is an inspiring example of what volunteer advocates can achieve.